Definition of Epidermis

Epidermis: The upper or outer layer of the two main
layers of cells that make up the skin. The epidermis is mostly made
up of flat, scale-like cells called squamous cells. Under the
squamous cells are round cells called basal cells. The deepest part
of the epidermis also contains melanocytes. These cells produce
melanin, which gives the skin its color.

The other main layer of the skin is the dermis, the inner layer of
skin, that contains blood and lymph vessels, hair follicles, and
glands. These glands produce sweat, which helps regulate body
temperature, and sebum, an oily substance that helps keep the skin from drying out. Sweat and sebum reach the skin's surface through tiny openings called pores.